I certainly don't claim to be the original discoverer of any of the tricks discussed below, nor is this a comprehensive list. These are just the ones I've encountered and remembered over the years, and which I'd like to share with you during this hot July day.
TelepathyInside the /usr/share/games directory on Ubuntu 10.04 is a utility called espdiff. If you call it with no arguments (in non-geek language, that just means open a terminal, type "espdiff" and press enter), it attempts to detect your "brainwave" activity, which is kind of cute. Add the --deep-brainwave-mode flag for extra sensitivity.
espdiff is part of the patch-utils package, which is much more than just an Easter egg. I've yet to figure out whether espdiff itself actually has any practical application, but it does come with its own man page, which gives it an aura of validity.
Ceci est un Easter eggThis Easter egg in aptitude is pretty well known, but this post wouldn't be complete if we didn't mention it. To see this joke in action, type:
aptitude -v moo
You'll be warned that there are no Easter eggs in your build of aptitude, but don't despair! Keep adding v's until you get to the end of this intricate joke, or just skip to the climax directly by typing:
aptitude -vvvvv moo
If you took high school French--or if you are French, or just like reading French books--you'll probably recognize this as a reference to Antoine de Saint-Exupéry's The Little Prince.
The Browser and the BeastSpeaking of books, I read one recently by the sociologist Christopher Kelty titled Two Bits: The Cultural Significance of Free Software. One of the arguments Kelty makes about open-source hackers is that they like parodying official religion--cf. Saint IGNUcius, the Church of Emacs and "The Cathedral and the Bazaar."
As an example of such behavior built right into Ubuntu, we need look no further than Firefox, which delivers this little Easter egg when you type "about:mozilla" in the address bar:
I'm neither a Biblical scholar nor a Mozilla developer, so I can't interpret this passage with any certainty. My rather uninformed guess, however, is that it refers to the "rebirth" of Netscape as Mozilla, back in the days before any except the geekiest among us even used Linux. And "Mammon" is probably Microsoft. But who knows.
For a less eschatological but equally amusing Easter egg, type "about:robots" in the Firefox address bar.
Fish vs. CowsBack in high school, much to the detriment of my calculus grade, I used to spend math class playing Phoenix on my TI-83 calculator. I was happy to discover, therefore, that Gnome comes with a slightly less sophisticated version of this game (and by "slightly less sophisticated," I mean "totally ridiculous") built right in.
To run it, press alt-F2 to open the Gnome run dialog, then type "gegls from outer space". It looks like this:
If this game brings you hours of fun, you may also enjoy what happens when you type "free the fish" into the Gnome run dialog. (Hint: when you get tired of having a little fish swimming around your desktop, you can get rid of it by killing the Gnome panel with the command "killall gnome-panel". The panel should restart itself automatically, sans fish.)
So, there you have it: a half-dozen fun things to do with your Ubuntu computer this summer when it's too hot to go outside (or vice-versa for those of you in the opposite hemisphere), or for when you just need your cow/fish/robot/Armageddon fix. Enjoy!